text: ###############################################################################
  # WaterTAP Copyright (c) 2021, The Regents of the University of California,
  # through Lawrence Berkeley National Laboratory, Oak Ridge National
  # Laboratory, National Renewable Energy Laboratory, and National Energy
  # Technology Laboratory (subject to receipt of any required approvals from
  # the U.S. Dept. of Energy). All rights reserved.
  #
  # Please see the files COPYRIGHT.md and LICENSE.md for full copyright and license
  # information, respectively. These files are also available online at the URL
  # "https://github.com/watertap-org/watertap/"
  #
  ###############################################################################
  """
  Tests for zero-order photothermal membrane model
  """
  import pytest
  
  
  from pyomo.environ import (
      Block,
      Var,
      Constraint,
      ConcreteModel,
      value,
      assert_optimal_termination,
  )
  from pyomo.util.check_units import assert_units_consistent
  
  from idaes.core import FlowsheetBlock
  from idaes.core.util import get_solver
  from idaes.core.util.model_statistics import degrees_of_freedom
  from idaes.core.util.testing import initialization_tester
  from idaes.generic_models.costing import UnitModelCostingBlock
  
  from watertap.unit_models.zero_order import PhotothermalMembraneZO
  from watertap.core.wt_database import Database
  from watertap.core.zero_order_properties import WaterParameterBlock
  from watertap.core.zero_order_costing import ZeroOrderCosting
  
  solver = get_solver()
  
  
  class TestPhotothermalMembraneZO:
      @pytest.fixture(scope="class")
      def model(self):
          m = ConcreteModel()
          m.db = Database()
  
          m.fs = FlowsheetBlock(default={"dynamic": False})
          m.fs.params = WaterParameterBlock(default={"solute_list": ["nitrogen"]})
  
          m.fs.unit = PhotothermalMembraneZO(
              default={"property_package": m.fs.params, "database": m.db}
          )
  
          m.fs.unit.inlet.flow_mass_comp[0, "H2O"].fix(120)
          m.fs.unit.inlet.flow_mass_comp[0, "nitrogen"].fix(1)
  
          return m
  
      @pytest.mark.unit
      def test_build(self, model):
          assert model.fs.unit.config.database is model.db
          assert model.fs.unit._tech_type == "photothermal_membrane"
          assert isinstance(model.fs.unit.water_flux, Var)
          assert isinstance(model.fs.unit.membrane_area, Var)
          assert isinstance(model.fs.unit.wat_flux, Constraint)
  
      @pytest.mark.component
      def test_load_parameters(self, model):
          data = model.db.get_unit_operation_parameters("photothermal_membrane")
  
          model.fs.unit.load_parameters_from_database(use_default_removal=True)
          assert model.fs.unit.recovery_frac_mass_H2O[0].fixed
          assert (
              model.fs.unit.recovery_frac_mass_H2O[0].value
              == data["recovery_frac_mass_H2O"]["value"]
          )
  
          for (t, j), v in model.fs.unit.removal_frac_mass_solute.items():
              assert v.fixed
              if j not in data["removal_frac_mass_solute"]:
                  assert v.value == data["default_removal_frac_mass_solute"]["value"]
              else:
                  assert v.value == data["removal_frac_mass_solute"][j]["value"]
  
      @pytest.mark.component
      def test_degrees_of_freedom(self, model):
          assert degrees_of_freedom(model.fs.unit) == 0
  
      @pytest.mark.component
      def test_unit_consistency(self, model):
          assert_units_consistent(model.fs.unit)
  
      @pytest.mark.component
      def test_initialize(self, model):
          initialization_tester(model)
  
      @pytest.mark.solver
      @pytest.mark.skipif(solver is None, reason="Solver not available")
      @pytest.mark.component
      def test_solve(self, model):
          results = solver.solve(model)
  
          # Check for optimal solution
          assert_optimal_termination(results)
  
      @pytest.mark.solver
      @pytest.mark.skipif(solver is None, reason="Solver not available")
      @pytest.mark.component
      def test_solution(self, model):
          assert pytest.approx(0.013, rel=1e-5) == value(
              model.fs.unit.properties_treated[0].flow_vol
          )
          assert pytest.approx(0.108, rel=1e-5) == value(
              model.fs.unit.properties_byproduct[0].flow_vol
          )
          assert pytest.approx(923.076923, rel=1e-5) == value(
              model.fs.unit.properties_treated[0].conc_mass_comp["H2O"]
          )
          assert pytest.approx(76.923077, rel=1e-5) == value(
              model.fs.unit.properties_treated[0].conc_mass_comp["nitrogen"]
          )
          assert pytest.approx(1000, rel=1e-5) == value(
              model.fs.unit.properties_byproduct[0].conc_mass_comp["H2O"]
          )
          assert (
              value(model.fs.unit.properties_byproduct[0].conc_mass_comp["nitrogen"])
              < 1e-6
          )
          assert value(
              model.fs.unit.properties_in[0].flow_mass_comp["nitrogen"]
          ) == value(model.fs.unit.properties_treated[0].flow_mass_comp["nitrogen"])
  
      @pytest.mark.solver
      @pytest.mark.skipif(solver is None, reason="Solver not available")
      @pytest.mark.component
      def test_conservation(self, model):
          for j in model.fs.params.component_list:
              assert 1e-5 >= abs(
                  value(
                      model.fs.unit.inlet.flow_mass_comp[0, j]
                      - model.fs.unit.treated.flow_mass_comp[0, j]
                      - model.fs.unit.byproduct.flow_mass_comp[0, j]
                  )
              )
  
      @pytest.mark.component
      def test_report(self, model):
  
          model.fs.unit.report()
  
  
  def test_costing():
      m = ConcreteModel()
      m.db = Database()
      m.fs = FlowsheetBlock(default={"dynamic": False})
      m.fs.params = WaterParameterBlock(default={"solute_list": ["nitrogen"]})
      m.fs.costing = ZeroOrderCosting()
      m.fs.unit = PhotothermalMembraneZO(
          default={"property_package": m.fs.params, "database": m.db}
      )
  
      m.fs.unit.inlet.flow_mass_comp[0, "H2O"].fix(120)
      m.fs.unit.inlet.flow_mass_comp[0, "nitrogen"].fix(1)
      m.fs.unit.load_parameters_from_database(use_default_removal=True)
  
      assert degrees_of_freedom(m.fs.unit) == 0
  
      m.fs.unit.costing = UnitModelCostingBlock(
          default={"flowsheet_costing_block": m.fs.costing}
      )
  
      assert isinstance(m.fs.costing.photothermal_membrane, Block)
      assert isinstance(m.fs.costing.photothermal_membrane.membrane_cost, Var)
  
      assert isinstance(m.fs.unit.costing.capital_cost, Var)
      assert isinstance(m.fs.unit.costing.capital_cost_constraint, Constraint)
  
      assert_units_consistent(m.fs)
      assert degrees_of_freedom(m.fs.unit) == 0
      initialization_tester(m)
  
      assert pytest.approx(4.719596, rel=1e-5) == value(m.fs.unit.costing.capital_cost)
  